The patch clamp measures current flow through ionic channels in natural membranes; these proteins control membrane function in cardiac muscle. Measurements are significantly limited by the electronics, particularly the resistor approximately 5x10-10 ohm needed to measure the current approximately 10-12A flowing through just one channel molecule. Our new circuit will use a small capacitor instead of the resistor because the capacitor is far more ideal. Prototypes show feasibility and much improved properties in all specifications tested so far. In Phase One of this project a complete instrument will be built and we will make biological measurements from a variety of muscle preparations in all configurations of the patch clamp. In Phase Two of the project the patch clamp amplifier will be turned into a practical and commercial product and a prototype of another instrument--optimized for physical scientists--will be built and hopefully brought to market.